1. Field of the Invention
The invention relates to an anti-fuse structure and an anti-fuse programming method, and more particularly, to an anti-fuse structure and an anti-fuse programming method having a predictable rupture point.
2. Description of the Prior Art
Programmable read-only memory (PROM), field programmable read-only memory (FPROM), and one-time programmable non-volatile memory (OTP NUM) are forms of digital memory where the setting of each bit is locked by a fuse or an anti-fuse structure.
As one type of the one-time programmable memory element, the anti-fuse structure, which performs the opposite function to a fuse structure, is permanently programmed by providing a current exceeding a specified limit to “blow” the anti-fuse structure. For example, an anti-fuse structure consist of a transistor is programmed when the gate dielectric breakdown occurs. In other words, a rupture point in a location on the gate dielectric layer that shorts a word line to a bit line is always expected when programming the anti-fuse structure.